First author: School of Life Sciences, Arizona State University, Tempe 85287; second and third authors: Department of Plant Pathology, Kansas State University, Manhattan 66506; and fourth author: U.S. Department of Agriculture-Agricultural Research Service, Plant Science and Entomology Research Unit, Manhattan, KS 66506
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Accepted for publication 16 May 2004.
Meta-analysis is a set of statistical procedures for synthesizing research results from a number of different studies. An estimate of a statistical effect, such as the difference in disease severity for plants with or without a management treatment, is collected from each study along with a measure of the variance of the estimate of the effect. Combining results from different studies will generally result in increased statistical power so that it is easier to detect small effects. Combining results from different studies may also make it possible to compare the size of the effect as a function of other predictor variables such as geographic region or pathogen species. We present a review of the basic methodology for meta-analysis. We also present an example of meta-analysis of the relationship between disease severity and yield loss for foliar wheat diseases, based on data collected from a decade of fungicide and nematicide test results.
© 2004 The American Phytopathological Society